Vented mounting block for circuit breaker



June 27, 1967 E. GRYCTKO 3,328,553

VENTED MOUNTING BLOCK FOB cmcum BREAKER Filed July 28,. 1966 I 0 M W H: 0%

United States Patent 3,328,553 VENTED MOUNTING BLOCK FOR CIRCUIT BREAKER Carl E. Gryctko, Haddon Heights, N.J., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Filed July 28, 1966, Ser. No. 568,500 9 Claims. (Cl. 200-468) This invention relates to circuit breakers, and more particularly relates to a vented mounting block which cooperates with a circuit breaker to support same; establish all necessary electrical connections between the breaker and the circuit being protected thereby; while at the same time provides a venting system for gases generated during circuit interruption which is completely external to the circuit breaker itself thereby permitting a reduction in the overall size thereof.

In recent years there has beenconsiderable effort expended in the electrical industry to reduce the size of circuit protective equipment. For example, in the area of small air circuit breakers of the type with which the instant invention is intended to cooperate, the industry has seen acceptance of one-half inch wide circuit breakers as a substitute for the long accepted one inch breaker. Further evidence of the present emphasis on reduction in size and simplicity in design is evidenced by United States patent application Ser. No. 587,709, filed Oct. 19, 1966-, entitled, Novel Circuit Breaker, and assigned to the assignee of the instant invention, where it may be seen that in addition to many other features, there has been achieved utmost simplicity in design and maximum reduction in overall size.

The instant invention furthers the miniaturization of small air circuit breakers such as the type described in Ser. No. 587,709 by providing a venting system for the gases which are generated during circuit interruption which is completely external of the circuit breaker casing and thus eliminates the necessity of providing a similar venting system within the breaker thereby permitting a reduction in its overall size. Specifically, small air circuit breakers generally include a pair of cooperating contacts which are separable in response to predetermined overload and/or fault conditions to interrupt the current flow therebetween and thus protect the load.

Until the cooperating contacts are separated by a sulficient distance, there is an arc struck therebetween, which are ionizes the air .within the vicinity of the contacts. Such ionized gases must be removed from the vicinity of the separating contacts if a re-strike across the separated contacts is to be prevented.

In the prior art, an elongated passageway is provided in one wall of the circuit breaker casing, with such passageway having one end communicating with the arc chamber of the circuit breaker, that is, the area within 'the circuit breaker where the arc is drawn between the separating contacts, and the other end passing through the casing wall to the atmosphere. However, the provision of such a passageway within the circuit breaker casing itself requires an intricately shaped casing and, furthermore, is diametrically opposed to design considerations which favor reducing the overall size of the breaker casing.

terruption. Specifically, the instant invention provides a mounting block of insulative material which includes an internal passageway communicating at one end with 'the atmosphere and at the other end with a circuit ice breaker supporting surface upon which a circuit breaker is adapted to be seated. Such circuit breaker includes a simple opening in the vicinity of the arc chamber, which opening is automatically aligned with the internal passageway of the mounting block whereby gases generated during circuit interruption may be channelled through the opening of the breaker, through the internal passageway of the mounting block, and out to the atmosphere.

As an advantageous feature of the instant invention, retaining means are provided on opposite sides of the circuit breaker supporting surface to removably seat the circuit breaker on the insulative mounting block. Preferably, the retaining means comprises a pair of stab-receiving receptacles each of which includes a pair of spring fingers adapted to biasingly grip associated depending terminal stabs of the circuit breaker. Additionally, a wire grip is electrically connected to each of such stabreceiving receptacles such that when the circuit breaker is seated on the circuit breaker supporting surface of the mounting block, all electrical connections will be electrically made from one wire grip to the other such that it is merely necessary to secure the load and line side conductors of the circuit being protected to the grips.

As a further feature of the instant invention, the circuit breaker and circuit breaker supporting surface of the insulative mounting block are provided with mating portions which can be cooperatively joined in only one manner which automatically aligns the opening of the circuit breaker with the end of the mounting block internal passageway which communicates with the circuit breaker supporting surface whereby any attempt to misalign the opening in the circuit breaker with the cooperating opening in the insulating mounting block will be frustrated. 7 Accordingly, it is an object of the instant invention to provide a mounting block for use with a cooperating circuit breaker which expels gases during circuit interruption.

Another object of the instant invention is to provide such a mounting block which includes a venting system for the gases generated within a circuit breaker during circuit interruption which eliminates the necessity of providing a venting system within the circuit breaker itself.

Still another object of the instant invention is to provide such a mounting block which permits a reduction in size of the circuit breaker which is to be supported thereby.

Still another object of the instant invention is to provide such a circuit breaker mounting block which includes a pair of stab-receiving receptacles and wire grips associated therewith which removably secures a circuit breaker to the mounting block while at the same time secures all electrical connections necessary between the line and load side wire grips.

Yet another object of the instant invention is to provide such a mounting block for use with a circuit breaker which generates ionized gases during circuit interruption, with portions of the mounting block and circuit breaker being keyed to assure that opening of the circuit breaker and the mounting block are always in alignment with the circuit breaker is seated on the mounting block.

Yet another object of the instant invention is to provide a mounting block which supports a circuit breaker, simplifies the electrical connection of the circuit breaker into the circuit being protected while at the same time permits the reduction in size of such circuit breakerby providing an external venting system for gases generated during circuit interruption.

Other objects and a fuller understanding of the instant invention may be had by referring to the following description and drawings, in which:

FIGURE 1 is an exploded perspective view of the mounting block of the instant invention shown as it is intended to cooperate with a circuit breaker; and

FIGURE 2 is a side view of the elements of FIGURE 1 in their assembled relationship.

'Turning to FIGURES 1 and 2, it may be seen that the vented mounting block of the instant invention comprises an insulative member 12, which, in the illustrative embodiment of FIGURE 1, includes two circuit breaker supporting surfaces generally indicated at 14 spaced on opposite sides of a barrier wall 16. Although the insulative mounting block 12 has been shown to include only two circuit breaker supporting surfaces 14 separated by a barrier 16, it is to be understood that mounting blocks constructed in accordance with the instant invention may have either a greater or lesser number of such circuit breaker supporting surfaces to receive either a greater or lesser number of circuit breakers in accordance with the needs of the user. To simplify description, only the cooperation of one circuit breaker supporting surface 14 and its associated circuit breaker 18 will be described in detail, it being understood that the same discussion is equally applicable to arrangements which include more than one such circuit breaker.

As schematically illustrated in FIGURE 2, circuit breaker 18 is of the type generally referred to in the art as a small air circuit breaker and characteristically includes a pair of cooperating contacts 20 and 22 mounted on a stationary terminal 26 and a movable contact arm 28, respectively. As well known in the art, contact arm 28 is movable to an open circuit position 38 to interrupt the flow of current from circuit breaker terminal 26 to a second circuit breaker terminal 32 in response to predetermined overload and/or fault condition occurring in the circuit being protected, as represented by conductors 34 and 36, as sensed by a tripping device section, generally indicated as 34. Although in no way intended to be limited by such disclosure, an example of such small air circuit breakers may be found in the aforementioned United States patent application Ser. No. 587,709.

For purposes of the instant invention it is sufficient to note that during circuit interruption. and until the contacts 20 and 22 are separated by sufficient distance, there will be an electric arc drawn therebetween. Such arc ionizes the air in the vicinity of the separating contacts whereby it becomes necessary to rid the interior of the circuit breaker 18 of such ionized gases in order to prevent a re-strike of the arc after the circuit has been interrupted. In the prior art, the elimination of such ionized gases was accomplished by providing a venting system within the circuit breaker such as 18, which prior art type of venting system customarily includes an internal arc chamber which is coupled to the atmosphere by means of an elongated passageway provided in the wall of the circuit breaker casing itself thereby necessarily requiring a more intricately designed casing, which, in addition to being more expensive to produce, inherently enlarges the overall dimensions of the casing of the breaker 18.

In contradistinction, the mounting block of the instant invention includes an internal passageway 38, one end of which is open to the atmosphere at 40 and the opposite end of which 42 communicates with an upper portion 44, of the circuit breaker supporting surface 14. In accord ance with the instant invention the provision of the venting passageway within the molded block, insulative block 12, permits the elimination of the equivalent venting system within the circuit breaker 18. Thus in FIGURE 2 it may be seen that the circuit breaker 18 includes merely an opening 46 beneath the contacts 20 and 22, which opening is aligned with the end 42 of internal passageway 38 thereby eliminating the need for intricately designing the casing of the circuit breaker 18 while at the same time permitting a reduction in the overall size thereof.

-In operation, upon separation of the cooperating contacts and 22, the ionized gases generated by the are drawn therebetween, will be channelled through the opening 46, through the passageway 38 and out the end thereof to the atmosphere as schematically represented by arrows 48.

To removably seat the circuit breaker 18 in cooperative relationship with respect to the insulative block 12 there are provided on each side of the circuit breaker supporting surface 14 a pair of stab-receiving receptacles 50 and 52. Such receptacles 50 and 52 each comprise a pair of upstanding spring-like fingers 54 and 56 which biasingly grip depending terminal stabs 26 and 32 of the breaker 18, when the breaker is seated on the circuit breaker supporting surface 14. Spring fingers 54 and 56 preferably comprise a single piece of metal, which is suitably secured to conductive bars 58 which are fastened to the insulative member 12 on opposite sides of the circuit breaker supporting surface 14 by means of screws 60 which pass through the conductive bars 58 and are received by apertures 62 provided in a lower surface 64 of the insulating mounting block 12. On the opposite end of conductive bars 58 are secured wire grips 66 which are provided with suitable clamping screws 68 by means of which the conductors 34 and 36 of the circuit being protected may be electrically and mechanically secured in place.

To insure that the opening 46 and the end 42 of passageway 38 of insulative mounting block -12 are in registry when the circuit breaker 18 is seated, the circuit breaker and mounting block are provided with matching key-way surfaces 70, 72 and 74, 76 which dovetail with one another to frustrate any attempt to install the circuit breaker in other than its intended position.

It should now be apparent that the mounting block 12 described above is simple, inexpensive to manufacture, and yet perform a multitude of functions. Specifically, the predesigned shape of the circuit breaker supporting surface 14 seats the breaker 1-8 in its correct position relative to the passageway 38; the stab-receiving receptacle means 50 and 52 firmly maintains the breaker 18 in its seating position while at the same time automatically completes the required electrical circuitry from wire grip 66 to wire grip 68; 'while at the same time the provision ofthe internal passageway 38 provides a completely external venting system which permits reduction in size of the breaker 18.

Although there has been described a preferred embodiment of this novel invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appending claims.

I claim: 1. A mounting block for use with a circuit breaker which expels gases upon separation of its cooperating contacts, said mounting block comprising:

an insulative member having a circuit breaker supporting surface and an internal passageway open to the atmosphere at one end thereof and communieating with said circuit breaker supporting surface at its other end thereof; and

retaining means secured to said insulative member for removably seating a circuit breaker on said circuit breaker supporting surface such that gases expelled by said circuit breaker will be channelled through said internal passageway and out said one end thereof to the atmosphere.

2. The mounting block of claim 1, wherein said retaining means comprises a pair of stab-receiving receptacles positioned on opposite sides of said circuit breaker supporting surface, each of said stab-receiving receptacles including a pair of upstanding spring fingers adapted to biasingly grip an associated stab depending from a circuit breaker seated on said circuit breaker supporting surface.

3. The mounting block of claim 2, and further including a pair of conductor-receiving grips, each of which is electrically connected to one of said stab-receiving receptacles whereby the seating of -a circuit breaker on said seating surface will establish all necessary electrical connections from one conductor-receiving grip to the other.

4. In combination: an insulative member having a circuit breaker support ing surface and a passageway open to the atmosphere at one end thereof and communicating with said circuit breaker supporting surface at its other end thereof; and a circuit breaker having a pair of cooperating contacts which are separable to interrupt current flow therebetween, said circuit breaker having an opening through which gases generated during current interruption may be expelled from said circuit breaker; said circuit breaker being removably seated on said circuit breaker supporting surface with said opening in alignment with said other end of said passageway;

whereby gases expelled by said circuit breaker will be channelled through said passageway and out said one end thereof to the atmosphere.

5. The combination of claim 4, wherein said circuit breaker and said insulative member have cooperating portions which permit said circuit breaker to be seated on said supporting surface only with said opening and said other end of said passageway in alignment.

*6. The combination of claim 4, and further including retaining means secured to said insulative member for removably seating said circuit breaker on said supporting surface.

7. The combination of claim '6, wherein said circuit breaker includes a pair of depending stabs, each of which is electrically connected to one of said pair of cooperating contacts, and said retaining means comprises a pair of stab-receiving receptacles positioned on opposite sides of said supporting surface, each of said stab-receiving receptacles including a pair of spring fingers which biasingly grip one of said depending stabs of said circuit breaker when it is seated on said supporting surface.

8. The combination of claim 7, and further including a pair of conductor-receiving grips, each of which is electrically connected to one of said stab-receiving receptacles whereby the seating of a circuit breaker on said seating surface will establish all necessary electrical connections from one conductor-receiving grip to the other.

9. The combination of claim 7, wherein said circuit breaker and said insulative member have cooperating portions which can be cooperatively joined only in a manner which permits said circuit breaker to be seated on said supporting surface with said opening and said other end of said passageway in alignment.

References Cited UNITED STATES PATENTS 1/1963 Ellsworth et al 200144 8/1965 Leonard 200144 

1. A MOUNTING BLOCK FOR USE WITH A CIRCUIT BREAKER WHICH EXPELS GASES UPON SEPARATION OF ITS COOPERATING CONTACTS, SAID MOUNTING BLOCK COMPRISING: AN INSULATIVE MEMBER HAVING A CIRCUIT BREAKER SUPPORTING SURFACE AND AN INTERNAL PASSAGEWAY OPEN TO THE ATMOSPHERE AT ONE END THEREOF AND COMMUNICATING WITH SAID CIRCUIT BREAKER SUPPORTING SURFACE AT ITS OTHER END THEREOF; AND RETAINING MEANS SECURED TO SAID INSULATIVE MEMBER FOR REMOVABLY SEATING A CIRCUIT BREAKER ON SAID CIRCUIT BREAKER SUPPORTING SURFACE SUCH THAT GASES EXPELLED BY SAID CIRCUIT BREAKER WILL BE CHANNELLED THROUGH SAID INTERNAL PASSAGEWAY AND OUT SAID ONE END THEREOF TO THE ATMOSPHERE. 